JP2849833B2 - Instant dry rice production method - Google Patents

Description

The present invention relates to a method for producing instant dry rice suitable as a raw material for home and industrial instant foods.

[Prior art] For example, ordinary cooked rice is washed with polished rice, soaked in water for 20 to 30 minutes, and then heat-treated such as cooked rice for 20 to 30 minutes.
Although cooked by steaming, to obtain good cooked rice, cooking time of about 1 hour or more is required, and thus instant dry rice that can be cooked in a few minutes is required.

In response to such demands, products such as puffed rice, which is obtained by steaming polished rice, drying dried gelatinized rice, and treating polished rice with high-temperature and high-pressure steam, and then releasing it under normal temperature and normal pressure to expand and dry, are processed. Although commercially available, all of them were unsatisfactory in taste, appearance or texture.

Therefore, the present applicant has previously proposed a method in which moisture-regulated polished rice is heated in a high-pressure gas, returned to normal temperature and normal pressure to obtain porous rice, and then dried. (Japanese patent application
63-129542) Instant dry rice produced by this method is porous and has good water absorbability. It absorbs rapidly when water is added, and then, when heated in a microwave oven or the like, has a better taste and appearance. In addition, cooked rice with significantly improved texture and the like can be obtained in a short time.

[Problems to be solved by the invention]

However, the instantly dried rice produced by the proposed method loses strength due to drying, and thus may be crushed by vibrations during movement or the like. The cooked rice obtained by cooking the instant dried rice has low stickiness and strength, and has a disadvantage that the texture is slightly inferior to that of ordinary cooked rice.

The method for producing instant dried rice of the present invention aims to solve such disadvantages.

[Means for solving the problem]

In order to achieve the above object, the present inventors have made various studies to improve the proposed method, and as a result, instead of heat-treating the polished rice after moisture adjustment in a high-pressure gas immediately, prior to this heat treatment, It has been found that when the polished rice is heat-treated in a conventional manner, the strength during drying can be increased, the elasticity after restoration cooking can be increased, and the texture can be improved while maintaining good taste and appearance.

The method for producing instant dried rice according to the present invention is based on the above findings. After washing the polished rice with a conventional method and adjusting the water content, the polished rice is heat-treated to a level before cooking for 9 minutes by a conventional method. Then, the rice grains are loosened, and then heat-treated in a high-pressure gas substantially free of moisture, then returned to a normal temperature and normal pressure state, and then dried, and the heat treatment by the ordinary method is further performed for 9 minutes. It is characterized by the level before cooking.

The polished rice is not limited in production place, type and quality.For example, domestic rice or foreign rice may be used, soft rice or hard rice may be used.In addition to new rice, old rice and old rice are usually used. The rice may be polished as rice. Further, these rices are usually non-glutinous rice, but may be glutinous rice, or both may be used in combination.

Next, the water content of the polished rice is adjusted to about 20 to 30% by an appropriate method such as immersing the polished rice in water for 1 to 2 hours or spraying the polished rice with water. I do. It should be noted that a surfactant, ethanol, or the like may be mixed with water to increase the permeability.

Next, as the heat treatment by a conventional method, steamed, boiled, cooked rice and the like are performed on the polished rice after the moisture adjustment. First, the steaming is performed by placing the polished rice in an arbitrary container such as a steamer or a steamer and exposing it to high-temperature steam for several minutes, and may be any of single-stage steaming, two-stage steaming, normal-pressure steaming, and pressure steaming.

In addition, boiling means heating the polished rice by a method such as pouring the polished rice into excess hot water. The rice is heated at a pressure slightly higher than the atmospheric pressure, for example, by heating the pot from the outside.

The degree of the heat treatment by the ordinary method such as steaming, boiling, and cooking rice is set to the level of ordinary rice, preferably the degree of appropriate incomplete treatment before cooking for 9 minutes, and the amount of milled rice and steam The amount, the temperature of steam, the heating temperature for cooking rice, etc. are appropriately determined and implemented. Further, since the rice after the heat treatment tends to be agglomerated, it is desirable to loosen the rice after the treatment.

Next, the heat treatment in a high-pressure gas, the rice after the heat treatment by the ordinary method is put into a container, and a high-temperature high-pressure gas is introduced into the container, or by any heating means. A high-pressure gas is introduced into a high-temperature vessel and pressurized and heat-treated. The gas used is carbon dioxide, nitrogen, argon, and helium, which are substantially free of moisture. In addition, any gas that can be used for food processing, such as air, can be selected.

In addition, since the pressurizing pressure, pressurizing temperature, and pressurizing time mutually affect each other, appropriate experiments should be performed in consideration of the expansion of the rice due to the decompression after the treatment and the final condition of the cooked rice that has been prepared by instant drying. It is preferable to determine it in a specific way.

For example, when using carbon dioxide, according to the findings of the present inventors, the pressure is 50 to 500 bar, and the processing temperature is 20 to 150 ° C.
The temperature is desirably set within the range described above, and more desirably, 50 to 100 ° C.

Next, as the drying treatment, any method such as hot air drying, vacuum drying, freeze drying and the like may be used.

(Operation)

If the polished rice after the absorption adjustment is subjected to a conventional heat treatment prior to the heat treatment in a high-pressure gas, the rice after the heat treatment is moderately gelatinized, and fine cracks in the rice grain structure are removed. The strength of the porous rice is increased by the heat treatment in a high-pressure gas, and the strength of the dried rice is improved. It is thought to bring a feeling of improvement.
It should be noted that the taste, appearance and the like are not deteriorated by steaming, boiling or cooking.

In particular, when the degree of the heat treatment by the ordinary method is the degree of the incomplete treatment before cooking for 9 minutes, when the rice after the heat treatment is unraveled, it is easier to cook the rice than when it is completely cooked, and any amount of rice is added. In addition to being able to be loosened without damaging the rice, the cooked rice has more elasticity than when cooked and the texture is improved.

〔Example〕

First, 200 g of polished rice was washed with water, immersed in water at a water temperature of 25 ° C. for 2 hours, sufficiently drained to adjust the water content of the polished rice, and then steamed under normal pressure for 30 minutes to obtain steamed rice. The steamed rice was stirred immediately while being brought into contact with cold air at 25 ° C. to loosen the rice grains, and then introduced into the pressure-resistant container 1 illustrated in the figure.

The pressure vessel 1 has a cylinder 2 filled with carbon dioxide.
Are connected to each other via a pump 3 and a heat exchanger 4, and the carbon dioxide in the cylinder 2 is raised to a pressure of 200 bar by the pump 3, and then heated to 55 ° C. 1 is press-fitted. In the figures, reference numerals 5 and 6 denote pressure regulating valves, 7 a pressure gauge, 8 a gas release valve, and a heater 9 mounted on the outer periphery of the pressure-resistant container 1. In order to efficiently perform the heat treatment, carbon dioxide may be passed through the pressure vessel 1 while maintaining a predetermined pressure and temperature, or a stirring means may be provided in the pressure vessel 1.

After the steamed rice is heated and pressurized in the pressure vessel 1 at a pressure of 200 bar and a temperature of 55 ° C. for 30 minutes, the gas release valve 8
After opening the carbon dioxide in the pressure vessel 1 and opening the rice, take out the rice from the pressure vessel 1 until the water content is about 10%.
Drying was performed with hot air at about ° C. As a result, about 190 g of milky white treated rice, that is, the desired instant dried rice was obtained.

In order to compare the strength of the instant dried rice at the time of drying with the previously applied method, the instant dried rice obtained by both methods was placed in a container and subjected to a vibration experiment. When about 30% of the whole was crushed, the instant dried rice according to the method of the present invention was about 3%, and the commercial value was greatly improved.

When 80 g of the instant dried rice was heated in 160 g of boiling water for 7 minutes, the rice was completely cooked, and the cooked rice was inferior to ordinary cooked rice in terms of taste, appearance and texture.

〔The invention's effect〕

As described above, according to the method of the present invention, prior to the heat treatment in a high-pressure gas substantially free of moisture, the heat treatment is performed by a conventional method. In addition to obtaining a product with little scratches and high commercial value, instant dry rice can be prepared that can cook cooked rice that is not only inferior to ordinary cooked rice in terms of the taste and appearance after cooking, but also has elasticity and texture, and instant The quality as food can be greatly improved.

In addition, since the heat treatment according to the conventional method is performed to a level before cooking for 9 minutes, the rice after the heat treatment is easily loosened, the workability is improved, and the texture when cooked is further enhanced.

[Brief description of the drawings]

The figure is a system diagram showing one embodiment of the method of the present invention. 1 ... pressure vessel, 2 ... cylinder, 3 ... pump, 4 ...
Heat exchanger, 8 Gas release valve, 9 Heater

Continuation of the front page (56) References JP-A-52-114034 (JP, A) JP-A-61-247348 (JP, A) JP-A-1-300865 (JP, A) Yoshito Sakurai, “General food Encyclopedia ", Tokyo Dobunshoin, May 25, 1968, p. 346 −347 (58) Field surveyed (Int.Cl. ⁶ , DB name) A23L 1/10

Claims (2)

(57) [Claims] 1. After washing the polished rice in a conventional manner to adjust the water content, heat the polished rice in a conventional manner for 9 minutes before cooking, loosen the rice grains, and then use a high-pressure gas substantially free of moisture. A method for producing instantly dried rice, comprising heating to room temperature, returning to normal temperature and normal pressure, and then drying. 2. The method according to claim 1, wherein the high-pressure gas is one of carbon dioxide, nitrogen, argon, helium, and air.